Blue-red aquarium incandescent lamp

ABSTRACT

A lamp for lighting an aquarium to enhance the appearance of the fish and accessories. The lamp uses an incandescent tungsten filament with a coating on its envelope to absorb the green and yellow light from the filament, so that the light emitted from the lamp is mainly blue and red.

United States Patent Alexander Tartakofl Beverly;

John Kelley Robertson, Lynn, Mass. 750,550

Aug. 6, 1968 Jan. 26, 1971 Sylvania Electric Products Inc.

a corporation of Delaware Inventors Appl. No. Filed Patented Assignee BLUE-RED AQUARIUM INCANDESCENT LAMP 1 Claim, 2 Drawing Figs.

US. Cl 313/112, 313/1 10,313/222 Int. Cl ..H0lj 61/40, HOlk l/26 Field of Search 313/110,

Primary Examiner-James W. Lawrencer Assistant Examiner-David OReilly Att0rneysNorman J. OMalley and Laurence Burns ABSTRACT: A lamp for lighting an aquarium to enhance the appearance of the'fish and accessories. The lamp uses an incandescent tungsten filament with a coating on its envelope to absorb the green and yellow light from the filament, so' that the light emitted from the lamp is mainly blue and red.

BLUE-RED AQUARIUM INCANDESCENT LAMP FIELD OF THE INVENTION This invention relates to incandescent lamps, that is to lamps having an incandescible filament in a sealed enclosing envelope, often called a bulb. The object of the invention is to enhance theappearance of fish and aquarium accessories when lighted by such lamps.

DESCRIPTION OF THE PRIOR ART Incandescent lamps have previously been used for lighting aquaria, but were available only in clear or white lamps or in colors which were not satisfactory for giving the fish a good appearance.

BRIEF'SUMMARY OF THE INVENTION BRIEF DESCRIPTION OF DRAWING Other features, objects and advantages of the invention will be apparent from the following specification, taken in connection with the drawing, in which:

FIG. I is a profile view, partly cut away, ofa lamp according to the invention; and

FIG. 2 is a graph of energy intensity versus wavelength of emitted light from the lamp.

DESCRIPTION OF EMBODIMENTS In FIG. I, the sealed tubular lamp bulb l contains a coiled tungsten filament 2, supported at its ends by lead-in wires 3,4 which extend through the press 5 of stem 6 and are connected respectively to the shell 7 of the base 8 and to the eyelet contact 9. The glass piece l0 supports the eyelet contact 9 from the shell 7 and insulated it therefrom. The base 8 is cemented to the bulb l in the usual manner.

The lamp bulb I has the coating ll over its outer surface, the coating being one which absorbs most of the green and yellow light emitted from the tungsten filament 2, and allows blue and red light to pass through.

In one embodiment of the invention, the tube l was of the type known as a T-lO that is about I V4 inch in diameter. The tube was about 4 inches long, measured to the beginning of the base, and was evacuated. The filament 2 was about 68 to 70 mm. long, and was held straight alongthe axis of the bulb l by the intermediate tungsten supports 12, which are affixed to lead-in wires 3 by the fused glass beads 13. The filament was designed for an input of 33 watts. About 0.765 gms. of the coating described below were on the bulb, the coating being about 0.00l inch thick.

The coating ll itself was made of: powdered uncolored glass frit, about 88 percent powdered titanium dioxide, which is white, about 9.8 percent; blue oxide pigment, such as cobalt oxide, 1.6 percent and a gold gel such as the so-called purple of Cassius, about 0.4 percent. The percentages are by weight; the purple of Cassius is the name for the oxides per precipitated from a solution of gold and tin chlorides, and is known as an artists color. Its color is, ofcourse, purple.

The above mixture is suspended in a liquid having I part of isopropyl alcohol and three parts of water by weight. About 50 parts of the powdered mixture are used in 20 parts of the liquid. The material can be applied to the outside of the bulb l by spraying or the like, and the bulb afterward dried and then heated to about l,200 F. to fuse the glass frit to the bulb l.

Because an incandescent filament emits much more red,

than blue, and some red .is transmitted throu h the coating together with the blue, the light from the bu b will consist mainly of blue and red with very little green and yellow. This is found to give a highly effective light for viewing fish. It produces very unusual lighting effects on the fish, which makes the aquarium quite attractive.

The transmission of the coating for blue light is somewhat greater than for red, but the high emission of red light by the incandescent filament makes the intensity of red emission from the lamp greater than for blue emission. As a result the lamp appears purple to the eye.

The actual emission of a 33 watt lamp according to the invention is shown in FIG. 2, where the abscissae are the various wavelengths emitted by the lamp, expressed in nanometers (millimicrons), and the ordinates are the relative energy inten sities of the radiation emitted from the lamp at the different wavelengths. The blue is low in intensity, despite the blue filter, because the black body curve for a filament operating at the comparatively low temperature of the vacuum (nongasfilled) lamp is not as great as the red. Nonetheless, the coating makes the blue higher with respect to the other colors than it would otherwise be, and cuts down the green and yellow considerably.

The bulb l'can be held in a standard socket for its screw base, the socket for example, being screwed or otherwise affixed to a flat U-shaped clip slipped over the top of the glass wall of an aquarium. The socket can be attached to a flat side of the U-shaped clip, on the side of the clip inside the aquarium, or can be held in some other way.

Although a particular embodiment has been described, this is by way of illustration rather than of limitation, and various modifications thereof will be apparent to a worker skilled in the art in accordance with the present specification.

We claim:

I. An electric lamp for aquarium lighting and the like, said lamp comprising an incandescent filament emitting red light and a substantially smaller amount of blue light, and also emitting yellow and green light, an envelope enclosing said filament, said envelope having a coating containing cobalt blue oxide and purple of Cassius in an amount sufficient to absorb the major portion of the yellow and green light while transmitting the red and blue light. 

1. An electric lamp for aquarium lighting and the like, said lamp comprising an incandescent filament emitting red light and a substantially smaller amount of blue light, and also emitting yellow and green light, an envelope enclosing said filament, said envelope having a coating containing cobalt blue oxide and purple of Cassius in an amount sufficient to absorb the major portion of the yellow and green light while transmitting the red and blue light. 